Same here! Can't download the new version because we don't have a page where to get it … seems like there are more security problems!
I also got the same problem. After login to jamf nation, the subpages don't show any content. There's just a blank page.
Still not working.
Especially in the light of required security fixes (https://www.jamf.com/jamf-nation/discussions/39219/jamf-pro-10-30-1-security-upgrade) required to work right now.
I Have the same issue. This is due to header misconfigurations.

I created a match and replace function to add the following header as a temporary fix. It allows to load to page but I get other front-end issues
Access-Control-Allow-Origin: *
Same problem for me (and many people in the MacAdmins Slack). Interestingly, my colleague can access it but I cannot. I cleared browsing data, tried Safari, Firefox, Chrome. I guess it's a problem with some of our accounts. I'm opening a ticket.
Fortunately I was able to get the installer from post from Michael P on Slack:
Quick URLs assuming download IDs are shared:
Linux: https://account.jamf.com/api/v1/release-versions/537/download-links/1233/signed-url
Windows: https://account.jamf.com/api/v1/release-versions/537/download-links/1235/signed-url
Mac: https://account.jamf.com/api/v1/release-versions/537/download-links/1236/signed-url
Manual: https://account.jamf.com/api/v1/release-versions/537/download-links/1234/signed-url
How to get URL yourself:
(Once logged into Jamf nation with current browser session)
Goto:
https://account.jamf.com/api/v1/release-versions/537/download-links
Grab the ID number for the OS version you want.
Put that ID into this URL:
https://account.jamf.com/api/v1/release-versions/537/download-links/<ID>/signed-url (edited)
Thanks @grahamrpugh . I already opened a ticket after posting here via Email on Friday evening. Just got an auto response mail. Nothing new from Jamf until now.
Same here. Cant download the Security Update, only empty pages
Count me in … - just to keep the thread on top. 
The issue is solved (for us). Thanks!
For me too, the problem is solved.
We apologize that some customers experienced an issue accessing Jamf Account subpages. As of 9 am CST today, 6/21, this issue has been resolved and everyone should have access to all Jamf Account pages.
Same here. And I am sure I allow cookies and JS.
It is particularly ironic that an attempt to create a support case sends me to empty https://account.jamf.com/support/open ... And I tried to contact support when I could not find any way to download Jamf Pro installer. The only clue was in https://docs.jamf.com/10.30.0/jamf-pro/install-guide-linux/Installing_Jamf_Pro_Using_the_Installer.html that has a link to https://www.jamf.com/jamf-nation/my/products that redirects to empty https://account.jamf.com/products...
What kind of a vicious circle is it?
So what's going on? Still nothing works. I can't get to the installer download page, can't open a support case to ask about it... All the pages I need under https://account.jamf.com are blank. The URLs in grahamrpugh's post say "You don't have access"...